Transferring cholesterol from HDL to LDL was beneficial in an environment with active LDL receptor activity.

“which in the days of very active ldr receptor activity was a great idea because then all the cholesterol went back to the liver and a cholesterol molecule is very expensive to make it costs 2780ps in a nasty environment like the Ice Age you want to conserve that molecule and the best way of conserving your cholesterol is by sending it back to the liver”